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perf: Rework the PMU methods

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Replace pmu::{enable,disable,start,stop,unthrottle} with
pmu::{add,del,start,stop}, all of which take a flags argument.

The new interface extends the capability to stop a counter while
keeping it scheduled on the PMU. We replace the throttled state with
the generic stopped state.

This also allows us to efficiently stop/start counters over certain
code paths (like IRQ handlers).

It also allows scheduling a counter without it starting, allowing for
a generic frozen state (useful for rotating stopped counters).

The stopped state is implemented in two different ways, depending on
how the architecture implemented the throttled state:

 1) We disable the counter:
    a) the pmu has per-counter enable bits, we flip that
    b) we program a NOP event, preserving the counter state

 2) We store the counter state and ignore all read/overflow events

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: paulus <paulus@samba.org>
Cc: stephane eranian <eranian@googlemail.com>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Lin Ming <ming.m.lin@intel.com>
Cc: Yanmin <yanmin_zhang@linux.intel.com>
Cc: Deng-Cheng Zhu <dengcheng.zhu@gmail.com>
Cc: David Miller <davem@davemloft.net>
Cc: Michael Cree <mcree@orcon.net.nz>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Peter Zijlstra
2010-06-16 14:37:10 +02:00
committed by Ingo Molnar
parent fa407f35e0
commit a4eaf7f146
14 changed files with 599 additions and 354 deletions
Download Patch File Download Diff File Expand all files Collapse all files

147
arch/sparc/kernel/perf_event.c
View File

@@ -658,13 +658,16 @@ static u64 maybe_change_configuration(struct cpu_hw_events *cpuc, u64 pcr)
enc = perf_event_get_enc(cpuc->events[i]);
pcr &= ~mask_for_index(idx);
pcr |= event_encoding(enc, idx);
if (hwc->state & PERF_HES_STOPPED)
pcr |= nop_for_index(idx);
else
pcr |= event_encoding(enc, idx);
}
out:
return pcr;
}
static void sparc_pmu_pmu_enable(struct pmu *pmu)
static void sparc_pmu_enable(struct pmu *pmu)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
u64 pcr;
@@ -691,7 +694,7 @@ static void sparc_pmu_pmu_enable(struct pmu *pmu)
pcr_ops->write(cpuc->pcr);
}
static void sparc_pmu_pmu_disable(struct pmu *pmu)
static void sparc_pmu_disable(struct pmu *pmu)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
u64 val;
@@ -710,48 +713,6 @@ static void sparc_pmu_pmu_disable(struct pmu *pmu)
pcr_ops->write(cpuc->pcr);
}
static void sparc_pmu_disable(struct perf_event *event)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
struct hw_perf_event *hwc = &event->hw;
unsigned long flags;
int i;
local_irq_save(flags);
perf_pmu_disable(event->pmu);
for (i = 0; i < cpuc->n_events; i++) {
if (event == cpuc->event[i]) {
int idx = cpuc->current_idx[i];
/* Shift remaining entries down into
* the existing slot.
*/
while (++i < cpuc->n_events) {
cpuc->event[i - 1] = cpuc->event[i];
cpuc->events[i - 1] = cpuc->events[i];
cpuc->current_idx[i - 1] =
cpuc->current_idx[i];
}
/* Absorb the final count and turn off the
* event.
*/
sparc_pmu_disable_event(cpuc, hwc, idx);
barrier();
sparc_perf_event_update(event, hwc, idx);
perf_event_update_userpage(event);
cpuc->n_events--;
break;
}
}
perf_pmu_enable(event->pmu);
local_irq_restore(flags);
}
static int active_event_index(struct cpu_hw_events *cpuc,
struct perf_event *event)
{
@@ -765,6 +726,74 @@ static int active_event_index(struct cpu_hw_events *cpuc,
return cpuc->current_idx[i];
}
static void sparc_pmu_start(struct perf_event *event, int flags)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
int idx = active_event_index(cpuc, event);
if (flags & PERF_EF_RELOAD) {
WARN_ON_ONCE(!(event->hw.state & PERF_HES_UPTODATE));
sparc_perf_event_set_period(event, &event->hw, idx);
}
event->hw.state = 0;
sparc_pmu_enable_event(cpuc, &event->hw, idx);
}
static void sparc_pmu_stop(struct perf_event *event, int flags)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
int idx = active_event_index(cpuc, event);
if (!(event->hw.state & PERF_HES_STOPPED)) {
sparc_pmu_disable_event(cpuc, &event->hw, idx);
event->hw.state |= PERF_HES_STOPPED;
}
if (!(event->hw.state & PERF_HES_UPTODATE) && (flags & PERF_EF_UPDATE)) {
sparc_perf_event_update(event, &event->hw, idx);
event->hw.state |= PERF_HES_UPTODATE;
}
}
static void sparc_pmu_del(struct perf_event *event, int _flags)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
unsigned long flags;
int i;
local_irq_save(flags);
perf_pmu_disable(event->pmu);
for (i = 0; i < cpuc->n_events; i++) {
if (event == cpuc->event[i]) {
/* Absorb the final count and turn off the
* event.
*/
sparc_pmu_stop(event, PERF_EF_UPDATE);
/* Shift remaining entries down into
* the existing slot.
*/
while (++i < cpuc->n_events) {
cpuc->event[i - 1] = cpuc->event[i];
cpuc->events[i - 1] = cpuc->events[i];
cpuc->current_idx[i - 1] =
cpuc->current_idx[i];
}
perf_event_update_userpage(event);
cpuc->n_events--;
break;
}
}
perf_pmu_enable(event->pmu);
local_irq_restore(flags);
}
static void sparc_pmu_read(struct perf_event *event)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
@@ -774,15 +803,6 @@ static void sparc_pmu_read(struct perf_event *event)
sparc_perf_event_update(event, hwc, idx);
}
static void sparc_pmu_unthrottle(struct perf_event *event)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
int idx = active_event_index(cpuc, event);
struct hw_perf_event *hwc = &event->hw;
sparc_pmu_enable_event(cpuc, hwc, idx);
}
static atomic_t active_events = ATOMIC_INIT(0);
static DEFINE_MUTEX(pmc_grab_mutex);
@@ -984,7 +1004,7 @@ static int collect_events(struct perf_event *group, int max_count,
return n;
}
static int sparc_pmu_enable(struct perf_event *event)
static int sparc_pmu_add(struct perf_event *event, int ef_flags)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
int n0, ret = -EAGAIN;
@@ -1001,6 +1021,10 @@ static int sparc_pmu_enable(struct perf_event *event)
cpuc->events[n0] = event->hw.event_base;
cpuc->current_idx[n0] = PIC_NO_INDEX;
event->hw.state = PERF_HES_UPTODATE;
if (!(ef_flags & PERF_EF_START))
event->hw.state |= PERF_HES_STOPPED;
/*
* If group events scheduling transaction was started,
* skip the schedulability test here, it will be peformed
@@ -1156,13 +1180,14 @@ static int sparc_pmu_commit_txn(struct pmu *pmu)
}
static struct pmu pmu = {
.pmu_enable = sparc_pmu_pmu_enable,
.pmu_disable = sparc_pmu_pmu_disable,
.pmu_enable = sparc_pmu_enable,
.pmu_disable = sparc_pmu_disable,
.event_init = sparc_pmu_event_init,
.enable = sparc_pmu_enable,
.disable = sparc_pmu_disable,
.add = sparc_pmu_add,
.del = sparc_pmu_del,
.start = sparc_pmu_start,
.stop = sparc_pmu_stop,
.read = sparc_pmu_read,
.unthrottle = sparc_pmu_unthrottle,
.start_txn = sparc_pmu_start_txn,
.cancel_txn = sparc_pmu_cancel_txn,
.commit_txn = sparc_pmu_commit_txn,
@@ -1243,7 +1268,7 @@ static int __kprobes perf_event_nmi_handler(struct notifier_block *self,
continue;
if (perf_event_overflow(event, 1, &data, regs))
sparc_pmu_disable_event(cpuc, hwc, idx);
sparc_pmu_stop(event, 0);
}
return NOTIFY_STOP;